Early blindsnakes are among the smallest serpents in the Neotropics. Although five species (Helminthophis flavoterminatus,
Liotyphlops anops, L. beui, L. schubarti, and L. ternetzii) may occasionally reach or exceed 1 ft (31 cm) in total length, most are considerably smaller, reaching adult lengths of only 6-10 in (15-25 cm) and adult weights of less than 0.1 oz (2.8 g). In addition to being short in length, these fossorial snakes are also quite slender, having maximum body widths of only 0.04-10.2 inches (1-5 mm) and aspect ratios (total length divided by body width) ranging from 32 to as high as 86.
Like other blindsnakes (Leptotyphlopidae and Typhlopi-dae), early blindsnakes have small, ventrally placed mouths; highly reduced eyes that are barely (if at all) visible beneath the overlying head scales; and cylindrical bodies covered with smooth, circular, and uniformly sized scales (they lack the enlarged belly scales present in most other forms of snakes). However, anomalepidids can be distinguished from other sympatric blindsnakes by the presence of two (or rarely three) anal shields (Leptotyphlops has only one and Typhlops has three to five) and teeth on both the upper and lower jaws (Leptoty-phlops lacks upper teeth and Typhlops lacks lower teeth). In addition, most anomalepidids have more than 20 rows of scales encircling the body, whereas all New World Leptotyphlops have 14 and all mainland Neotropical Typhlops have 20 or fewer. Finally, most members of the family are characterized by a distinctive color pattern in which the body is uniformly dark in color (black or dark brown), but the head and often at least parts of the tail are light in color (white, yellow, or pink). The four species of Anomalepis stand as exceptions to this generalization, however, being uniformly brown or reddish brown in coloration.
In all species of Anomalepididae the snout is bluntly rounded in shape, and in all genera except Typhlophis the scales surrounding the snout are somewhat enlarged. These enlarged scales not only reduce friction between the snake's head and the soil during burrowing, they also house numerous pressure-sensitive sensory organs. The tail is universally short (1-3.4% of the snake's total length) and may terminate in a sharp, needle-like apical spine (T. squamosus and the seven species of Liotyphlops), or end more bluntly as in other snakes (Anomalepis, Helminthophis, and T. ayarzaguenai).
Early blindsnakes are also characterized by a suite of unique internal anatomical features. The most noteworthy of these features are an elaborate, M-shaped hyoid (the skeletal element that supports the tongue, and which in other snakes is V- or Y-shaped), a relatively short tongue, and a pair of peculiar "orbital bones" that are involved in the suspension of the upper jaws. (Though traditionally called "orbital bones," it has recently been established that these bones have nothing to do with the formation of the bony orbit.) Additionally, like many other basal snakes, at least some species of Liotyphlops retain a vestigial pelvic girdle. However, no pelvic elements have been found in Anomalepis, Helminthophis, or Typhlophis.
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